Further contribution to conductometric determination of carbon dioxide

In a previous publication a method has been shown by which it is possible to determine carbon dioxide by conductometric measurements. This method can be applied for single as well as for continuous determinations of carbon dioxide evolved from a reaction system

Secondary a-Deuterium Isotope Effects in the Reaction of 2-Phenylethyltrimethylammonium Ion by Hydroxide Ion in Aqueous Solution and by Ethoxide Ion in Ethanol

Secondary a-deuterium isotope effects in the reaction of 2-phenylethyltrimethylammonium iodide with hydroxide ion in aqueous solution at 97.0° and with ethoxide ion in ethanol at 40.0° have been found to be very small. The results .suggest that the hydrogen compound reacts slightly faster than the deuterium compound. The secondary a-deuterium isotope effect in the reaction of 2-phenylethyl bromide with sodium ethoxide in ethanol is appreciably larger and ammounts to 9 per cent per deuterium atom at 59.8°. The mechanistic implications of these results are discussed

Secondary a-deuterium isotope effects in the reaction of 2-phenylethyltrimethylammonium ion by hydroxide ion in aqueous solution and by ethoxide ion in ethanol

Secondary a-deuterium isotope effects in the reaction of 2-phenylethyltrimethylammonium iodide with hydroxide ion in aqueous solution at 97.0° and with ethoxide ion in ethanol at 40.0° have been found to be very small. The results .suggest that the hydrogen compound reacts slightly faster than the deuterium compound. The secondary a-deuterium isotope effect in the reaction of 2-phenylethyl bromide with sodium ethoxide in ethanol is appreciably larger and ammounts to 9 per cent per deuterium atom at 59.8°. The mechanistic implications of these results are discussed

Secondary deuterium isotope effects in some S N1 and E2 reactions

An a-deuterium isotope effect kH/kn of 170/o was found in the E 2 reaction of 2-phenylethyl-l,l-d2 bromide with sodium ethoxide in ethanol. This supports the Streitwieser change-of-hybridization theory and the associated explanation of the absence of such effects in S N2 reactions as being due to the proximity of the incoming group. The magnitude of the ~- and a-deuterium isotope effects in the SNl and E2 reactions of some alkylsulphonium salts were determined and compared with the isotope effects of the corresponding alkyl-halides. An explanation for these differences is given

Dependence of rates of substitution reactions of pentacyanoaquoiron(II) ion on ionic strength

The second-order rate constants (k) of substitution of water in pentacyanoaquo:iron(II) ion by nitrite, thiocyanate, sulphite or nitrobenzene were determined at various ionic strengths {I) in aqueous solution at 25 oc. The following slopes of the plot of log k versus J'h were obtained : 2.9 (No2-·), 2.5 (SCN-), 4.4 (S0a2-), and zero (nitrosobenzene)

Removal of Glucocorticosteroids and Anesthetics from Waterwith RO/NF Membranes

This work addresses the removal of glucocorticosteroids (hydrocortisone, HYDRO; and dexamethasone, DEXA) and anesthetics (procaine, PROCA; and lidocaine, LIDO), from water with commercially available reverse osmosis/nanofiltration (RO/NF) membranes. The RO/NF experiments were of long-run type (24 h) in order to accomplish steady-state and to obtain accurate rejection of the selected compounds. The removal of the examined compounds with the RO (XLE, SWC1, LFC–1) and the tight NF (NF90) membranes was higher than 98 %. Relating the solute rejections to membranes\u27 properties has shown that the dominant rejection mechanism of the examined pharmaceuticals by all the membranes was the size exclusion effect. Rejection factors for hydrophilic HYDRO and DEXA compounds confirm that they do not adsorb onto the active layer of the selected membranes. LIDO and PROCA, slightly hydrophobic compounds, had lower rejections after 24 h treatment compared to initial values, and probable they were adsorbed onto polymeric matrix of active layers

Kinetics and mechanism of base hydrolysis of (dimethyl sulphoxide)penta-amminecobalt(III) ions

Data are presented showing that at constant 0.02 M OH- the rate of the base hydrolysis of the (NH3)5 Co(DMS0)3+ ion increases with an ·increase in the nonaqueous component in aqueous-organic mixtures containing methanol, ethanol, DMSO ( = dimethyl suiphoxide), acetone or dioxane. The enhancement in the rate, which amounts to more than 100 fold in organic component-rich mixtures, is discussed in terms of an increase of the basicity of the mixed solvents due to the decreasing salvation of OH-. The base hydrolysis of the DMSO-complex ion in the presence of 1 M anion Y and 0.125 M Off yields 12.8, 9.9, 7.8, 1.8, and 3.7 mol 0/o (NHs); CoY from (NH3); CoX for the competing anions Ns-, ScN-, N02-, OAc-, and S04 2-, respectively. The mechanistic implications of these results are discussed in terms of SNlCB and Id mechanisms